The primary objective is to modify the current formulation of CAPRONOR (registered trademark), a biodegradable device based on poly (epsilon caprolactone), designed for the sustained delivery of contraceptive levels of levonorgestrel for a minimum period of one year. Phase II clinical trials had indicated that serum levels of levonorgestrel were lower than desired for near 100% effective contraception, and there was a downward drift over time. Also the shelf-life of the current device needs to be increased. Toxicological studies and Phase I clinical trial also will be done to evaluate the performance of the modified CAPRONOR (registered trademark) device under this contract.